Gases and gas law are pretty much an abstract topic which baffles many students. However, this need not be so if you can understand the key terminologies and concepts for the topic. The following are important terminologies and concepts for STPM Form 6 regarding the topic of “Gases and Gas Law”. You may use it as your notes too.
STPM Form 6 – Terminology and Concepts : Gases and Gas Law
- Gas Pressure – the force per unit area exerted by a gas through collisions against a defined area of the container wall.
(Gas molecules collide more frequently with the container wall → gas pressure increases)
- Collision Frequency – the rate at which molecules in the gas system collide with each other and the wall of the container.
(Collision frequency ↑ when temperature ↑, concentration of gas particle ↑, mean free path ↓)
- Collision force – the force exerted by a gas particle during collision between it and the container wall.
(greater momentum and shorter time of contact increase the force of impact)
Collision force can be increased by → temperature increase → greater velocity & greater momentum
- Volume – region within the walls of a container.
(actual volume that a gas molecule can occupy is the volume of the container minus the volume of the other gas molecules, because no two gas molecules can occupy the same volume at the same time.)
- Concentration (gas) – the number of gas particles per unit volume in a container.
(Homogeneous gas – used to determine the gas concentration)
- Mean Free Path – the average distance a particle can travel before colliding with another particle.
- Temperature (gas) – total kinetic energy of a system.
- Average Kinetic Energy – the mean energy of a particle in that system.
(energy of each particle ↑ , average kinetic energy ↑ → ↑ temperature)
Adapted from The Berkeley Review (2004) pg4.